Development of a Method to Model Flexible Hose in FE Linear Dynamics Simulations

Linear dynamics simulations are performed on engine components to ensure structural integrity under dynamic loading. The finite element model of the engine assembly must be prepared accurately to avoid under or over design of the engine components. Flexible hoses are present at pipe routings and modeling them in simulations is a challenge because the stiffness of the composite is not known. The hose under study in this paper is a rubber composite with a knitted reinforcement layer. A multiscale modelling approach is presented to characterize the hose stiffness. A representative volume element geometry i.e., unit cell representation of the composite, consisting of the knitted yarn and surrounding rubber is used to establish orthotropic elastic properties at microscale, by performing finite element homogenization using the ANSYS material designer module. The homogenized properties are assigned to the macroscale hose geometry to perform modal analysis simulation in free-free and fixed-fixed condition. To validate the finite element model, experimental modal analysis is performed on the hose with the same boundary condition. Fundamental natural frequencies and mode shapes obtained from simulations and experiments are compared which shows good agreement. A predominantly automated approach to characterize the stiffness of the hose is presented and it is suggested that the hose shall be modelled using orthotropic elastic properties in linear dynamics simulations for a more accurate finite element model.